Skid steer loaders are known to provide a high degree of maneuverability and a wide range of applications in the agricultural, industrial and construction fields. These loading machines generally include an engine, a boom assembly and an operator's cab mounted to a main frame supported by four ground wheels. A main drive system is coupled to the engine. The loading machine is maneuvered by driving the wheels on one side at a different speed and/or direction from those on the other side resulting in a revolving motion governed by the relative speed of the wheels. The boom assembly in a skid steer loader typically includes a pair of load arm assemblies pivotably mounted directly to the main frame or a support frame extending upwardly therefrom. Material handling attachments such as a bucket or other working attachment are usually mounted on the forward end of the load arm assemblies. A separate hydraulic system is usually employed in skid steer loaders to power the boom assembly between raised and lowered positions via hydraulic cylinders coupled to the load arm assemblies. This same system may be used to actuate one or two tilt cylinders which pivot or "curl" the working attachment relative to the load arm assemblies. Typically, a pair of hand or foot controls installed in the operator's cab control the flow of hydraulic fluid to the load arm and tilt cylinders.
Besides material handling buckets, various other attachments such as pallet forks, earth augers, backhoes, trenchers, etc., which include their own particular hydraulic motors and/or cylinders, are commonly mounted to the boom assembly. An auxiliary hydraulic system is used to control the flow of hydraulic fluid between a pump on the frame and the hydraulic motor in the vicinity of the front-mounted attachment. It is the usual practice in the prior art for the flow of hydraulic fluid to be channeled from the pump to the hydraulic motor associated with the attachment by means of a plurality of hydraulic tubes which are generally directed along the load arm assemblies.
In the use of skid steer loaders as described above, the load arm extends past the side of the cab and can effect the visibility of the operator. In the prior art, the load arms extend linearly in a downward and forward direction from their pivoting attachment to the upwardly extending supports at the rear of the machine, and thus are in the operator's line of sight when lowered. A problem may arise in occcasional damage to the hydraulic tubing feeding the bucket or other working attachment on the front of the load arm assemblies due to adverse environmental conditions.
Accordingly, there is a desire for a load arm assembly capable of being mounted on the loading machine frame so as to maximize the lateral visibility of the operator when the boom assembly is in the lowered position and the operator wishes to perform turning maneuvers. Also, it is desirable to provide a safety arm having a relatively simple but reliable structure for preventing a boom assembly from lowering beyond a given height. Furthermore, it is advantageous to protect, conceal and maintain the integrity of the hydraulic tubing supplying the bucket or other working attachment.
It is one object of the present invention to provide a loading machine with a load arm assembly having a shape and a construction conducive to improved operator visibility when lowered. It is another object of the present invention to provide a load arm assembly for protectively and concealably retaining along the underside thereof a supply line arrangement feeding a working attachment. It is also an object of the present invention to provide a pivotable load arm assembly having an anti-lowering arrangement for maintaining the boom assembly at a predetermined raised position, such as for servicing or the like. Yet another object of the present invention is to provide a load arm assembly having a double channel construction capable of withstanding the working stresses associated with operation of a mobile loading machine and facilitating manufacture.
One aspect of the invention relates to a mobile loading machine having a frame and an operator's cab mounted thereon, and a load arm assembly adapted to be pivotably mounted at a rear end of the frame and to support a tool between a lowered position and a raised position at a forward end thereof. The load arm assembly includes an outer load arm for supporting the tool, an inner load arm pivotably mounted to the frame independent of the cab, and an intermediate load arm integrally connected between the outer and inner load arms. The intermediate load arm is in overlapping relationship with the inner load arm and is fixed thereto in a joint such that the intermediate load arm is positioned alongside a lowermost portion of the cab and the inner load arm projects upwardly and rearwardly of the cab from the intermediate load arm when the load arm assembly is in the lowered position to maximize the lateral visibility of the operator from the cab when the load arm assembly is lowered. The inner load arm and the intermediate load arm have intersecting longitudinal axes, the included angle between the axes being greater than 90.degree.. The intermediate load arm has a top wall, a bottom wall and a pair of connecting sidewalls extending downwardly beyond the bottom wall. The inner load arm has an upper wall, a lower wall and a pair of connecting side segments, the upper wall and side segments of the inner load arm being received within the top wall and the sidewalls of the intermediate load arm. The load arm assembly includes a brace connecting the bottom wall of the intermediate load arm with the lower wall of the inner load arm. The inner load arm extends downwardly and forwardly between the frame and the cab, the intermediate load arm extends downwardly and forwardly alongside the cab and the outer load arm extends substantially downwardly in front of the cab when the tool is in the lowered position.
Another aspect of the invention relates to a loading machine with a tubular load arm assembly having a top wall and a bottom wall connected by a pair of sidewalls for supporting a power tool fed by a supply line arrangement running alongside the load arm assembly. A retaining device is positioned on the bottom wall between extended portions of the sidewalls for protecting and concealing the supply line arrangement.
Another aspect of the invention relates to a mobile loading machine having a movable load arm assembly for supporting a power tool connected with a supply line arrangement. An inverted, generally U-shaped channel defines a top wall and a pair of spaced apart sidewalls depending therefrom. A bottom wall is connected across the sidewalls and closes the U-shaped channel to form a tubular support member. A clamping device is secured to the bottom wall for retaining the supply line arrangement adjacent thereto, the depending sidewalls being constructed and arranged to conceal, protect and allow accessibility to the supply line arrangement. The depending sidewalls are substantially parallel to one another and the bottom wall is substantially parallel to the top wall. The bottom wall may be in the form of an upright U-shaped channel having a transverse portion and a pair of upright side portions, each of which is secured to an inside surface of a respective sidewall. The supply line arrangement includes a hydraulic cylinder and a pair of hydraulic tubes for feeding hydraulic fluid to the hydraulic cylinder. The clamping device includes an upper yoke member connected to the underside of the bottom wall, a bottom yoke member engageable with the upper yoke member and a fastener threadably received in aligned openings formed in the upper yoke member, the lower yoke member and the bottom wall so as to clampingly retain the supply line arrangement between the upper and lower yoke members beneath the bottom wall and between the depending sidewalls. The depending sidewalls extend downwardly beyond the clamping device.
Yet another aspect of the invention relates to a loading machine having a frame, a load arm assembly pivotably mounted to the frame and a power device connected to the load arm assembly and movable between an extended position and a retracted position for respectively obtaining a raised condition and a lowered condition of the load arm assembly. The improvement resides in an anti-lowering arrangement located on an underside of the load arm assembly for holding a power device in the extended position and preventing lowering of the load arm assembly. The anti-lowering arrangement includes a safety bar pivotably mounted upon a pair of sidewalls depending from the load arm assembly between an inoperative position wherein the safety bar is protectively retained between the sidewalls and disengaged from the power device, and an operative condition wherein the safety bar is released from between the sidewalls to pivot downwardly by gravity into obstructing contact with the power device so as to prevent retraction of the power device and maintain the raised condition of the load arm assembly.
Still yet another aspect of the invention relates to an anti-lowering arrangement for a loading machine having a frame, at least one load arm assembly pivotably connected to the frame and a power device associated with the load arm assembly and movable between a retracted position and an extended position for lowering and raising the load arm assembly. A safety bar has a first end pivotably mounted to the load arm assembly and a second end movable between an inoperative position wherein the bar is connected to the load arm assembly and spaced from the power device, and an operative position wherein, with the power device in the extended position, the bar is released and pivots away from the load arm assembly into obstructing contact with the power device to hold the power device in the extended position and prevent lowering of the load arm assembly. The power device is a hydraulic cylinder having a rod portion telescopically mounted within a cylinder portion. The second end of the safety bar is engageable with both the rod and cylinder portions when the power device is in the extended position. The safety bar is mounted above the power device, and is formed as an inverted, U-shaped channel having an upper wall and a pair of depending sidewalls provided with a pair of aligned openings therethrough. The load arm assembly includes a pair of depending sidewalls formed with aligned apertures therethrough. A retaining pin is passable through the aligned openings of the safety bar and the aligned apertures of the load arm assembly to retain the safety bar is in the inoperative position. The length of the retaining pin is longer than the distance between the sidewalls of the load arm assembly so that the ends of the pin will extend beyond the sidewalls of the load arm assembly when the safety pin is in the inoperative position. The safety bar is concealed between the sidewalls of the load arm assembly when the safety bar is in the inoperative position. The length of the safety bar is substantially equal to the length of the rod portion of the hydraulic cylinder. The first end of the safety bar and one end of the power device are pivotably mounted to the depending sidewalls of the load arm assembly.
Various other objects, features and advantages of the invention will be made apparent from consideration of the following description taken together with the drawings.